Switch



sept. 9, 1941.

W. W. HELLE swITcx-r Filed May 9, 1938 3 Sheets-Sheet 1 Sept. 9, 1941.w. w. HELLE SWITCH Filed May 9, 193s A 3 Sheets-Sheet 2 rllll A Sept. 9,1941.

w. w. HELLE 2,255,115

SWITCH.,

Filed May 9, 1958 s sheets-sheet :s

Patented Sept. 9, 1941 UNITED sTATEsVPATENT oFF-ical SWITCH Warren W.Helle, Hinsdale, Ill.

Application May 9, 1938, Serial No. 206,701

7 Claims.

quickly from the closed position to the open position and numerousdevices have been provided for accomplishing this result. It has alsobeen recognized that a fairly rm contact pressure between the closedcontacts is desirable, Aand most of the switch mechanisms have providedsuch firm pressure while the switch is at rest. However, in switches inwhich the operating mechanism supplies the contact pressure (asdistinguished from knife switches, in which the pressure is supplied bythe jaws which grip the blades) there has been a common fault which maybe described as a gradual decrease of pressure during movement of theactuating mechanism before it has moved far enough to operate the switchand break a circuit, for instance.

Such switches have generally connected the actuating lever to themovable switch member through some sort of a spring for the purpose ofproviding a snap movement. With the movable switch member in oneposition and the spring pressing it firmly in that position, theactuating lever or handle would be moved, and as it moved it would shiftthe spring until the spring had passed the dead-center position and waspressing the movable member in the opposite direction, at which timethis member would snap to its alternative position. It will be observedthat in all such switches the spring must inevitably pass through adead-center position in which it is not supplying any contact pressureand as it approaches this dead-center position the contact pressurewhich it exerts must be diminishing. Of course, if the actuating leveris moved quickly the duration of the diminishing pressure is rathershort and may be harmless. On the other hand, in the case of someautomatic devices, such as a valve controlling switch operated by afloat for keeping the water at a given level in a tank, the movement ofthe actuating lever will be very gradual with the result that there maybe a substantial length of time during which the contact pressure at theclosed contacts is too low. 'I'he result of such low contact pressuremay be very harmful to the switch because it results in high Contactresistance or possibly even a slight separation of thecontacts-resulting in arcing and burning of the contacts.

An object of the present invention therefore is to provide a switch inwhich the actuating mechanism maintains an adequate contact pressureuntil the instant that it snaps the movable switch member to separatethe contacts so that even with a slow movement of the operating handlethere will be no appreciable time during which thercontact pressure isinadequate. In general, it may be stated that this is accomplishedaccording to the present invention by providing a spring actuatingarrangement in which the actuating spring snaps from the position urgingthe movable member in one direction to the position urging the movablemember in the other direction so that, until the yspring snaps, thecontact pressure will be firm and then instantaneously the fun pressurewiu be shifted to the opposite direction. In the preferred illustratedforms of the invention the predominant force of the spring as applied tothe movable member is a compressional force and this full compressionalforce is exerted in one direction until the spring is twisted by theactuating lever in such a way that, although the twisting movement maybe gradual initially, the compressional force remains and is thereforeshifted instantaneously as the spring eventually snaps to itsalternative position. In short, the mechanism applies a relativelyconstant pressure to the movable member and shifts the direction of thisforce instantaneously.

Another object of the invention is to provide a more durable anduniformly acting spring for switches of the general type in which aspring is utilized to flip a contact closing and opening member inopposite directions successively.

Further objects and advantages of the invention will be apparent fromthe following description and from the accompanying drawings, in

which:

Fig. 1 is an elevation of one form cf switch embodying this invention,the cover being partially broken away for the sake of clarity.

Fig. 2 is a. sectional view taken on the line 2 2 of Fig. 1 showing oneform of pivotal connection between the spring and the movable switchmember.

Fig. 3 is a perspective view of one form of movable member.

Fig. 4 is a perspective view of the pivotal link connecting the springwith the movable member.

Fig. 5 is a perspective View of the spring.

Fig. 6 is a view corresponding to Fig. l but showing a modified form ofthe invention.

Fig. 7 is a view showing the structure of Figl 6 which pivotallyconnects the spring with the movable member.

Fig. 12 is a sectional view of another modificai tion of the inventiontaken on the line I2-I2 of n Fig. 1a.

Fig. 13 is a sectional view taken approximately on the line I3-I3 ofFig. 12.

Fig. 14 is a view corresponding to Fig. -13 but showing the switch inits alternative position.

Fig. 15 is a perspective view of the movable member of Figs. 12 to 14.

Fig. 16 is a sectional view showing another use of the spring of thisinvention.

Although this invention may take numerous forms, only a few have beenchosen'for illustration. of the preferred forms as to general operation.The switch includes a housing II, an .actuating lever I2 and anoperating or contact carrying member I3. The` actuating lever I2 isconnected to the operating member I3 through a relatively The form shownin Figs. 1 to 5 is typical y closely coiled spring I 4 in a constructionwhich comprises a major feature of this invention. In one commercialembodiment of the invention the coils are 5*," apart longitudinally ofthe spring at the body portion of each coil. Since the construction atrst glance may seem to be similar to other switches in including thethree main elements I2, I3 and I4, it may be pointed out that the springI4, though positioned at the top of Fig. 1, is pressing the operatingmember I3 downwardly about pivot I5 instead of urging it upwardly asthose skilled in the art would expect from the position of spring I4.The significance of this unusual arrangement can be described betterafter describing other details of the switch. The switch shown in Fiss.1 to 5 is a multicircuit switch including four pairs of contacts I3, II,I8 and I3, only one contact of each pair being visible in Fig. 1. Theoperating member is provided with circuit bridging contacts 2I, 22, 23and 24, which in fact may be considered parts of the operating member.In the position shown in Fig. 1 bridging contact 22 is bridging theflxed contacts I1, and bridging contact 23 is bridging the fixedcontacts I9. Upon operation of the lever I2 the operating member wouldbe shifted sothat the bridging contacts 2I and 24 would .tacts asoccasion may require. Inasmuch as the operating member operates in thehead of a T-shaped housing, holes may be provided or drilled in thefour1 positions shown in Fig. 1 and a pair of contacts provided in eachposition.

In order to obtain satisfactory performance of a contact switch of thisgeneral type (as disitingiushed from the more expensive, morecomplicated and bulkier knife switch) it is necessary that a firmpressure be maintained between all contacts. Since the available contactpressure is all derived from spring I4, it is desirable that thisPressure be divided evenly between the various contacts, and,accordingly, the bridging contacts are all spring mounted. Thus, as seenin Fig. 3, the bridging contacts 2I and 22 are both urged to theirextreme positions by a spring 23 which operates at the centers of thebridging contacts so that each bridging contact may rock about thecenter point to accommodate itself to unevenness in the positioning ofthe fixed contacts. Furthermore, the fixed contacts may be adjustablypositioned as illustrated in Fig. 1.

Maintenance of contact pressure None of these precautions will inthemselves insure the maintenance of the contact pressure while theswitch is being operated. It is evident that to shift the operatingmember I3 from the position shown in Fig. 1 to the alternative positionit is' necessary that the force applied thereto be shifted from adownward direction to an upward direction as seen in Fig. 1. As thisforce passes through the dead-center position the contact pressure mustof course be zero. Furthermore, as the preure approaches the dead-centerposition the contact pressure would, in an :ordinary switch, graduallydecrease. If the cong I3 is shifted through the entire dead-center zoneinstantaneously or with a snap action no matter how slowly the actuatinglever I2 is operated. The reason for this can be explained better withrespect to Figs. 6 and '1, in which the parts are numbered the same inso far as they have been described heretofore. l

In Fig. 6, as in Fig. l, the spring Il is a coil spring which is undercompression as well as being distorted laterally. It wil be observedthat 'respectively bridge contacts I3 and contacts I8. A

it presses against the wall portion 28 of the housing, which thereforemay be considered a stop for th'e spring. This wall portion holds thespring I4 under compression by restricting its lateral distortion. 'Ihecompressional force of the spring is exerted on the operating member I3in the direction of the arrow 29 which maintains the operating-member I3in its illustrated position, thus maintaining an adequate contactpressure. The lateral ilexing of the spring Il probab'ly causes it toexert some pressure in the direction of arrow 2l but the spring issulciently compressed so that any force in. the direction of the arrow30 is greatly overbalanced by the compressional force and hence theforce in the direction of arrow lll may be ignored. As the actuatinglever I2 is moved upwardly, it comes to the position shown in full linesin Fig. 'I bel fore the operating member I3 moves. When the actuatinglever I2 is in the position shown in full lines in Fig. '7 the spring Ilwill have assumed approximately the position shown in full lines in Fig.7, but it will be observed that its compressional force is still exertedon the operl ating member I3 in the direction of the arrow 29. It willbe understood of course that the compressional force of the spring isexerted longitudinally of that portion of the spring which is closest tothe operating member I3. Now as the actuating lever I2 moves even aslight amount further toward the dotted line position inFig. '7, thespring I4 snaps to the dotted line position shown in Fig. 7. It will beobserved that in this position its compressional force is in thedirection of arrow 30 and hence the operating membei` I3 immediatelysnaps to the position shown in dotted lines.

Snap movements of the operating members can of course be obtained inother manners. It is important to notice therefore that this switchprovides an instantaneous shift of pressure through the dead-centerzone. In Fig. 7 the spring I4 is shown in full lines approximately inits dead-center position butthe pressure it exerts is still in thegeneral direction of arrow 29. In other words, although the spring maypass slowly through its dead-center zone, the pressure shiftsinstantaneously. It shifts not as the spring passes through itsdead-center zone but as the spring snaps away from the deadcenter zoneafter passing therethrough.

Pivotal spring connection It will be observed from Fig. 7 that when thespring snaps from the full line position to the dotted line position itsleft end changes its angle with respect to the operating member I3. Inthe full line position it approaches the operating member in thedirection of arrow 29, whereas in the dotted line position it approachesthe operating member in the direction of arrow 30. It appears thereforethat in order to get full advantage of the instantaneous shift ofpressure the spring I4 must have a pivotal connection of some sort withthe operating member I3. Two generaltypes of this pivotal connectionhave been shown. In Fig. 1 the spring bears on a stirrup 32 which swingswithin the operating member I3 from notches 33, the stirrup havingprotruding ends 34 which rest in said notches. The spring acts on thebottom or central mem ber of this stirrup. In the formof the inventionillustrated in Figs. 1 to 5 the spring is shown provided with a shoe 36which is notched to ride on the stirrup 32. However,` the stirrup 32 maybe provided with a projecting lug extending up into the spring. Theillustrated notch, however. may have some advantage in permittingpivotal movement between the stirrup and the spring to supplement thepivotal movement between the stirrup and the operating member I3.

In the form of the invention shown in Figs. 6 to 11, and as seen best inFig. 9, the stirrup is omitted and instead the spring I4 is providedwith a shoe 38 which rides directly in the not-ches 33. The notches 33may be provided with a widened seat 39 which permits the shoe 38 toslide from side to side therein to increase the torque arm of the springpressure about the pivot I just as the swinging of the stirrup 32 seemsto increase the torque arm of the spring I4 abouttage of long life andlongitudinal compressibility and it has the further important advantagedue to the configuration thereof of confining its -fiexing under thecircumstances here described to the plane perpendicular to the pivot l5.This causes the spring to track in a single longitudinal space and makesit unnecessary to provide any side guides for the spring, which wouldin,- evitably increase the friction of its movements and would thereforebe likely to make the results less satisfactory than with the presentspring.

In Fig. 10 a modified form of the bridging contacts has been shown,being given the numbers 2i', 22', etc. It will be observed that in thisinstance the bridging members are bowed and their resiliency is reliedupon in lieu of spring 26. Their bowed shape permits them to rock so asto equalize the contact pressure between the two ends of each bridgingcontact.

Figs. 12 to 14 illustrate another form of operating member, which inthis instance has been numbered 4I. In this instance the operatingmember is provided with a fulcrum vane 42 instead of being mounted on apivot. The vane 42 rocks in a. groove 43 formed in the housing 44, whichmay otherwise be similar to the housing 28. The vane 42 may rest againstthe bottom of the groove or it may merely serve as a key, operatingmember 4I being provided with rockers 46 resting on the Wall of housing44.

A different form of bridging contact has been shown in the operatingmember 4I. It comprises a rigid plate 41, which may be considered thebridging portion, having' a contact bearing portion 48 and a reinforcingfiange 49 which rides in a groove 5I in operating member 4 I The flange49 is in turn provided with a central extension 52 (Fig. 13) and is bentover at its rear end at 53 to limit the movement of the bridging portion41. The bridging portion 41 is urged toward the contacts I 6 by acentral spring 54. The ange 49 and extension 52 should fit looselyenough within the operating member 4I to permit the bridging portion 41to rock enough to equalize the contact pressure.

In Fig. 16 an additional form of switch has been shown which showsanother use for the fiat spring I4. In this instance it is simplyslipped into slots 6I and 62 in the actuating member 63 and theoperating member 64 respectively by being slid into the end of the slotwhich is exposed when the cover is removed. The actuating member 63would of course be provided with a suitable actuating lever external ofthe casing.

From the foregoing it is seen thatl a switch is provided in which thecontact pressure is adequately maintained by the operating spring untilthe instant that the spring snaps to its alternative position and henceoperates the switch by moving the operating member thereof. It may beobserved that this operating spring really serves as two elements. Thatnearer the operating member is a pressure exerting portion whichconstantly exerts a pressure on the operating member. The more remoteportion of the spring is a direction controlling portion which snapsfrom the position shown in full lines in Fig. 7 to the position shown indotted lines, thus changing instantaneously the direction of the forceapplied by the pressure portion. Because of its flat coil shape theflexing of the spring is confined substantially entirely to the desireddirection so that its action is always the same. I

Although I have described my invention in the preferred embodiments, itis understood that the invention is not limited thereto, but changes andmodifications may be made therein, all within the scope of the appendedclaims.

I claim:

1. A switch including an actuating member, a pivoted contact bridgingmember having an edge rim and a cavity below the edge rim, a springsupport pivotally mounted on said edge rim and having a portionextending into said cavity, a s'pring operatively connected at one endto said actuating member and supported at the other 4end upon saidspring support with said other end of said spring extending into saidcavity.

2. A switch including actuating means having a pivot portion on which itis pivoted, contact bridging means having an axis portion, a coiledrelativelyiiat spring operatively connected at one end with saidactuating means, support means supporting the spring at the other endwith said support means having a pivot portion pivotally connected withsaid bridging means at a point displaced substantially longitudinallyfrom said axis portion and intermediate said axis portion and theactuating means pivot portion in said switch, with the distance betweenthe other end of saidspring on the spring support means and theactuating means pivot portion being greater than the distance betweenthe actuating means pivot portion and the point of pivotal connectionfor the spring support means and the contact bridging means, and stopmeans for limiting the lateral bowing of thespring in each of twopositions of rest therefor positioned so as to maintain said coiledspring under compression at said positions of rest and provide a springforce for application to the spring support means.

3. A switch including a pivotal bridging member movable between twopositions, axis means pivotally supporting said bridging member, apivotal actuating member having an axis, a compressed coil springarranged for bending between said actuating member and bridging member,

said spring being operable to move the Vbridging member from one of saidpositions to the other in response to the movement of said actuatingmember and to retain said bridging member in the position into which itis moved, said spring being connected at one end to said actuatingmember for side to side bending movement thereby, means for limiting thesidewise bending movement of said spring to two extreme positions, withthe spring force applied on said bridging member when the spring is inone of said extreme positions being opposite from that when the springis'in the other of said extreme positions, andA means pivotallyconnected to the bridging member andy pivotal independently thereof forsupporting the opposite end oi' said member, with saidaxis means andaxis portion being arranged in a substantially common sectional plane ofsaid bridging member and said axis means being displaced away from saidaxis portion, with said axis portion being positioned in a substantiallylongitudinal direction vintermediate the axis for said actuating memberand said axis means, said spring supporting means on movement of saidactuating member permitting said spring to snap from one of its extremepositions to the other prior to any substantial change in the directionof the force thereof being applied to said bridging member for movingthe same.

4. In an electric switch having operatively associated xed contact meansand movable contact means, the combination of means for eiiecting a snapmovement oi said movable contact means in response to a relatively slowactuating movement for operating said switch including a pivotedbridging member carrying said movable contact means and having anopening therein. a pivoted actuating member, a spring arranged incompression betweenl said actuating and bridging members and laterallymovable intermediate its ends in response to movement of said actuatingmember to move said bridging member to open and close said movable andfixed contact means, with one end of said spring being connected to saidactuating member, a spring support pivotally mounted on said bridgingmember and having a portion extending into said opening, with the otherspring end being supported on said extending portion, the pivotal axesof said supporting member and bridging member being arranged in a commonsectional plane in said bridging member, and means for limiting thelateral movement of said spring to two operating positions, said springin one of said operating positions being bent in a direction to apply apressure on said bridging member in one direction to one side of saidplane, and being reversely bent in the other oi said operating positionsto exert a pressure on said bridging member in an opposite direction,with movement of said actuating member progressively deflecting saidspring until it becomes compressively unstable for one of said bentpositions at which time it immediately snaps to a reversely bentposition and-with said spring pressure being applied in one direction onsaid bridging member until immediately after-said snapping action.

5. A switch including insulating frame means, actuating means, a contactbridging member having side portions and an opening therebetween, apivot portion on said bridging member pivotally supporting said memberon said frame means, a substantially U-shaped spring support member witha connecting portion extending into said opening and being pivotallyconnected with said bridging member at said side portions and at anaxial line which is intermediate said connecting portion and saidactuating means in a substantially longitudinal direction in saidswitch, a relatively 'fiat coiled spring operatively connected at oneend with said actuating means and extending into said openingat saidother end and operatively connected with said connecting portion of saidspring support, stop means for limiting the lateral bowing of saidspring in a position of rest thereof and positioned so as to maintainsaid spring under compression to provide a spring force for applicationto said spring support member and contact bridging member, and contactmielns on said bridging member movable therew 6. In an electrical switchincluding a pivoted actuating member, a pivoted bridging means having-anopening therein, means operatively connecting said actuating member andbridging means including a coil spring, with movement of said actuatinglever moving said spring with a sidewise motion to move said bridgingmeans, said spring being connected at one end to said actuating member,with the other end thereof pivotally supported on said bridging means,and a spring supporting element having an axis portion pivotally mountedon said bridging means with a second portion extending within saidopening, said other spring end being supported on said second portionand within said opening so as to thereof pivotaily supported on saidbridging member, and means having an axis portion pivotally mounted onsaid rim portion and a second portion extending within said opening,said other spring end being supported on said second portion andextending into said opening so that the distance between said two springends is normally greater than the distance between said one spring endand said axis portion.

